Barcelona coach Gerardo Martino has admitted that he does not know the seriousness of the injury suffered by Lionel Messi on Saturday.

The Argentine forward was replaced soon after scoring against Almeria in the first half of their 2-0 away win in La Liga.

"Apparently Messi picked up small muscle strain in the back of his right leg when he scored," Sky Sports News quotes Martino as saying. "It's hard to say anything else until he undergoes additional tests."

Messi will undergo further medical tests on Sunday to determine the extent of his injury.